The Sunnah for a person during Salah is to look at the place of Sujud
Q: Where should a person look while offering Salah (Prayer)?
A: It is an act of the Sunnah to look at the place of Sujud (Prostration during Prayer) while standing and during Ruku` (bowing) but while sitting for Tashahhud (a recitation in the sitting position in the second/ last unit of Prayer) or between the two Sujuds one should look at his fingers as mentioned in the Sunnah of the Prophet (peace be upon him).
Q: Which is better for a man offering Salah in Al-Haram; to look at Al-Ka`bah or at the place of Sujud?
A: It is prescribed in all Prayers and in every place to look at the place of Sujud because this is more beneficial in bringing about submission and concentration except during Tashahhud. Therefore, it is an act of the Sunnah (supererogatory act of worship following the example of the Prophet) to look at the fingers. May Allah grant all success!
Source : Ibn Baz fatwa